Welding Compression fitting and thermowell

[mattwood2000]

Hi folks I'm building a sankey fermenter similar to the Brewers Hardware kit except on a larger scale. I'm going to use a 6" triclover fitting so that I can easily clean and inspect the inside of the keg.

I also want to add a thermowell, blowoff tube and linear racking arm just like the Brewers Hardware kit.

My question is on the welding. I have a buddy who does fabrication for a living and just my luck wants to get into brewing so we're going to trade metal work for beer and brewing tips.

I have not welded since I took it in college a number of years ago but I just want to understand what other people may have done for a similar idea. The Brewers Hardware kit has a compression fitting welded to the triclover cap. The only compression fittings I've seen out there are NPT x compression. Are there compression fittings out there designed to be welded? I suppose I could get an MPT x compression fitting and then have my buddy weld a FPT bulkhead to the cap but that just doesn't seem right to me. I'm just wondering how the guys at Brewers Hardware did it without using a bulkhead? Did they just cut off the threads and weld the fitting?

Also any thoughts or tips on welding the thermowell in the cap?

Thanks, Matt.

 

[tophmck]

Before going this route, you'll want to make sure your buddy has experience with sanitary welding. While sanitary welds are optional on the hot side, they're really essential for a fermentation vessel.

This doesn't really answer your question, but if I had access to free sanitary welding, I'd skip the compression fitting altogether and go with a rotating racking arm -- something like this:
http://nanobrewing.blogspot.com/2011/01/fermenters.html

 

[mattwood2000]

Thanks for the reply. I'm not worried about his welding capability. As far as I understand sanitary welds are pretty common sense and straight forward. Purging the interior with argon, cleaning and pickling the weld afterwards are what I understand to be the process.

I thought about the rotating arm but I've read that they are prone to leaking and I figured the compression fitting on the top would be cheaper and rule out any leaking issues. I do intend to rack under pressure when this project is finished.

 

[Bobby_M]

There are two ways to do this that I can think of off the top of my head. Have a machine shop Turn the threads down to a smooth surface, drill equal sized hole in the TC cap, weld form the inside and grind smooth. The shortcut is to just make the hole in the TC large enough for the threads to fit through, weld and grind. This latter method may reveal a couple pits at the fitting/TC joint but you can touch it up with a spot weld and regrind it. Not elegant but should be sanitary. Since this welding is happening on an easily accessible surface, the adherence to sanitary welding methods is less important because you can clean up the welds quite well. Just don't grind/wire-wheel with iron-contaminated tools.

 

[mattwood2000]

Thanks Bobby_M I think he has the equipment to turn the threads but I'll have to ask him over a couple of beers. I would rather do it that way than the shortcut method.

 

[hannahjo]

Sheet metal fabrication is interesting if you are passionate about it. All the best for your new endeavour!